DOCSLIB.ORG

EEE 531: Semiconductor Device Theory I

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
EEE 531: Semiconductor Device Theory I EEE 531: Semiconductor Device Theory I Instructor: Dragica Vasileska Department of Electrical Engineering Arizona State University Topics covered: 1. Introduction to MOSFET operation EEE 531: Semiconductor Device Theory I 1. Introduction • Firs proposal for a MOSFET 5 Critical Dimension ] Cell Edge device was given by s r e t Lilienfeld and Heil in 1930. e m 1 o r • First operational device was c i m [ made in 1947 at Bell Labs. n o i • Since then, the MOSFET s n e m 0.1 dimensions have been con- i D tinuously scaled to achieve 0.05 1990 1995 2000 2005 2010 more functions on a chip. yYeear r FFrroomm S SIAIA r rooaaddmmaapp f foorr sseemmicicoonndduuccttoorrss ( (11999977)) EEE 531: Semiconductor Device Theory I • MOSFET is a four-terminal device. Basic device configura- tion is illustrated on the figures below. Side-view of the device Top-view of the device Basic device parameters: channel length L channel width W oxide thickness d junction depth r ox substrate dopingj N A EEE 531: Semiconductor Device Theory I • There are basically four types of MOSFETs: (a) n-cnannel, enhancement mode device G I S D D symbol n+ n+ p-type SC V V G T (b) n-cnannel, depletion mode device G S D I symbol D n+ n+ p-type SC V V G T EEE 531: Semiconductor Device Theory I (c) p-cnannel, enhancement mode device I G D V S D T V symbol G p+ p+ n-type SC (d) p-cnannel, depletion mode device I G D S D V symbol T V G p+ p+ n-type SC EEE 531: Semiconductor Device Theory I • The role of the Gate electrode for n-channel MOSFET: VV == 00 source drain GG VV >> VV source drain GG TT Positive gate voltage does two things: (1) Reduces the potential energy barrier seen by the electrons from the source and the drain regions. (2) Inverts the surface, and increases the conductivity of the channel. EEE 531: Semiconductor Device Theory I • The role of the Drain electrode for n-channel MOSFET: dn/dE VV == 00,, VV >> 00 GG DD dn/dE source E Large potential barrier allows only few C electrons to go from the source to the drain drain (subthreshold conduction) dn/dE VV >> VV ,, VV >> 00 GG TT DD dn/dE source E Smaller potential barrier allows a large drain C number of electrons to go from the source to the drain EEE 531: Semiconductor Device Theory I • Qualitative description of MOSFET operation: G ((aa)) VV >> VV, , VV >> 00 ((ssmmaalll)) S D GG TT DD Variation of electron density n+ n+ along the channel is small: p-type SC I D VD G ((bb))VV >> VV,, V V >> 00 ((llaarrggeerr)) S D GG TT DD + + Increase in the drain current n n reduces due to the reduced conductivity of the channel at p-type SC the drain end. EEE 531: Semiconductor Device Theory I G ((cc))VV >> VV,, V V == VV --VV S D GG TT DD GG TT n+ n+ Pinch-off point. Electron density at the drain-end of the p-type SC channel is identically zero. G ((dd))VV >> VV,, V V >> VV --VV S D GG TT DD GG TT n+ n+ Post pinch-off characteristic. L The excess drain voltage is dropped across the highly re- p-type SC sistive pinch-off region deno- ted by L. EEE 531: Semiconductor Device Theory I • IV-characteristics (long-channel devices): I D (c) (d) Linear (b) region Saturation (a) region V D EEE 531: Semiconductor Device Theory I 17 3 N A 810 cm , dox 3 nm VG 0.8 V, VD 20 mV, VT 0.33 V ] V e [ c E d n a b n o i t c u d n o drain C source D i st an ce [ m ] [m] Distance EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 20 mV Accumulation of carriers Surface inversion ] 3 - m [ y t i s n drain e d n o r source t c e l E m] [ ce Dista tan nce is [m] D EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 0.2V, VT 0.33 V Negating effect of the drain ] 3 - m [ y t i s n drain e d n o r t c source e l E m] Dis [ tance ce [m tan ] Dis EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 0.56V, VT 0.33 V ] V e [ c E d n a b source n o i t c u d n drain ] o m C [ ce n ta is Distance [m] D EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 0.56V, VT 0.33 V ] 3 - m [ y t i s n e d drain n o r t source c e l E m] [ ce an Dista ist nce [m] D EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 0.9V, VT 0.33 V Pinched-off ] channel 3 - m [ y t i s n e drain d n o r t source c e l E m] [ e D nc istance sta [m] Di EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 1.56V, VT 0.33 V 3D View Contour plot 0.1 ] V e [ c 0.08 E d n 0.06 a b n source o i 0.04 t ] c u m d [ n 0.02 o e C c n drain a t 0 Distanc is 0 0.05 0.1 0.15 e [m] D Distance [m] EEE 531: Semiconductor Device Theory I VG 0.8 V, VD 1.56V, VT 0.33 V Pinched-off channel ] 3 - m [ y t i s n e d n drain o r t c e l source E ] [m D ce istance [ tan m] Dis EEE 531: Semiconductor Device Theory I EEE 531: Semiconductor Device Theory I Instructor: Dragica Vasileska Department of Electrical Engineering Arizona State University Topics covered: 2. Gradual channel approximation for current calculation (A) square-law theory (B) bulk-charge theory (C) transconductance, output conductance and series resistance (D) limitations of the two models EEE 531: Semiconductor Device Theory I 2. Gradual channel approximation • This model is due to Shockley. • Assumption: The electric field variation in the direction parallel to the SC/oxide interface is much smaller than the electric field variation in the direction perpendicular to the interface: z G W x S D oxide y n+ n+ L dF dF x y p-type SC dx dy EEE 531: Semiconductor Device Theory I • Recall the expressions for the threshold voltage for real MOS capacitor: 1 Gate voltage: VT 2F 2qN Aks0 2F VFB Cox Q 1 Qit f Qot Qm Flat band voltage: VFB MS ot m q Cox Cox Cox Cox • Beyond the point that determines the onset of strong inversi- on ( =2 ), any excess charge on the gate balanced with s F excess charge in the semiconductor, is given by: QG QB QN Ctot VG VT QN Cox VG VT QB QB QB s QB 2F • Based on how we consider Q , we have: B (A) Square-law theory: Q = 0 B (B) Bulk-charge theory: Q 0 B EEE 531: Semiconductor Device Theory I (A) Square-law theory • The charge on the gate is completely balanced by Q (x), i.e: N QN (x) Ctot VG VT V (x) V = 0 S E V(x) FS V x D E x=0 C E = E - V • Total current density in the channel: FD FS D dn dV J qn F(x) qD qn n n n dx n dx negligible Note: Total current density approximately equal to the electron current density (unipolar device). EEE 531: Semiconductor Device Theory I • Integrating the current density, we obtain drain current I : D W yc (x) dV I dz dy qn(x, y) (x, y) D n 0 0 dx dV yc (x) W qn(x, y)n (x, y)dy dx 0 Q(x) N eff High-resolution transmission electron micrograph of the interface dV between Si and SiO Q (x) W 2 N eff dx (Goodnick et al., Phys. Rev. B 32, p. 8171, 1985) dV 2.71 Å 3.84 Å C W V V V (x) ox eff G T dx EEffffeeccttiivvee eelleeccttrroonn mmoobbiilliittyy,, iinn wwhhiicchh i inntteerrffaaccee--rroouugghhnneessss iiss ttaakkeenn i innttoo aaccccoouunntt.. EEE 531: Semiconductor Device Theory I • The role of interface-roughness on the low-field electron mobility: Phonon Coulomb 1500 (aN + bN )-1 400 s depl ] ] s s - - -1/3 V N V 300 / s 1000 17 3 / 2 N 7 10 cm A 2 m m c c [ [ 200 y experimental data y t i t l i 500 uniform i l i b b step-like (low-high) o o retrograde (Gaussian) M M 0 100 1015 1016 1017 1018 1012 1013 Doping [cm-3] Inversion charge density N [cm-2] s Interface-roughness BBuullkk ssaammpplleess SSiiiinnvveerrssiioonn l laayyeerrss EEE 531: Semiconductor Device Theory I • The experimentally observed universal mobility behavior is due to the dominant surface-roughness influence on the low- field electron mobility under strong inversion conditions. • Various models proposed for the variation of the effective transverse electric field upon the inversion (N ) and deple- s tion (N ) charge density: depl Stern and Howard: F 11 N N eff 32 s depl Matsumoto and Uemura: Feff 0.5Ns Ndepl Krutsick and White: <z> Feff 0 .5Ns 1 Ndepl (a=0.5 and b<1) W EEE 531: Semiconductor Device Theory I • There are several empirical expressions for the effective field dependence of the low-field electron mobility: Effective-field dependence: 1105 342 , n,eff 0.657 p,eff 0.617 1 Feff / 30.5 1 Feff /15.4 Gate-voltage dependence: 0 n,eff , 0.02 0.08 1/V 1 (VGS VT ) • Universal mobility eff N N N behavior: A3 A2 A1 N A1 N A2 N A3 Feff EEE 531: Semiconductor Device Theory I • We now use the conservation of current argument, to get: V L D IDdx Weff Cox VG VT V (x) dV 0 0 W C I eff ox V V V 1V 2 , for V V V D L G T D 2 D D G T • This last result represents the expression for the current, valid up to the pinch-off point.
Load more

Recommended publications
  • Chapter1: Semiconductor Diode
    Chapter1: Semiconductor Diode. Electronics I Discussion Eng.Abdo Salah Theoretical Background: • The semiconductor diode is formed by doping P-type impurity in one side and N-type of impurity in another side of the semiconductor crystal forming a p-n junction as shown in the following figure. At the junction initially free charge carriers from both side recombine forming negatively c harged ions in P side of junction(an atom in P -side accept electron and be comes negatively c harged ion) and po sitive ly c harged ion on n side (an atom in n-side accepts hole i.e. donates electron and becomes positively charged ion)region. This region deplete of any type of free charge carrier is called as depletion region. Further recombination of free carrier on both side is prevented because of the depletion voltage generated due to charge carriers kept at distance by depletion (acts as a sort of insulation) layer as shown dotted in the above figure. Working principle: When voltage is not app lied acros s the diode , de pletion region for ms as shown in the above figure. When the voltage is applied be tween the two terminals of the diode (anode and cathode) two possibilities arises depending o n polarity of DC supply. [1] Forward-Bias Condition: When the +Ve terminal of the battery is connected to P-type material & -Ve terminal to N-type terminal as shown in the circuit diagram, the diode is said to be forward biased. The application of forward bias voltage will force electrons in N-type and holes in P -type material to recombine with the ions near boundary and to flow crossing junction.
    [Show full text]
  • An Integrated Semiconductor Device Enabling Non-Optical Genome Sequencing
    ARTICLE doi:10.1038/nature10242 An integrated semiconductor device enabling non-optical genome sequencing Jonathan M. Rothberg1, Wolfgang Hinz1, Todd M. Rearick1, Jonathan Schultz1, William Mileski1, Mel Davey1, John H. Leamon1, Kim Johnson1, Mark J. Milgrew1, Matthew Edwards1, Jeremy Hoon1, Jan F. Simons1, David Marran1, Jason W. Myers1, John F. Davidson1, Annika Branting1, John R. Nobile1, Bernard P. Puc1, David Light1, Travis A. Clark1, Martin Huber1, Jeffrey T. Branciforte1, Isaac B. Stoner1, Simon E. Cawley1, Michael Lyons1, Yutao Fu1, Nils Homer1, Marina Sedova1, Xin Miao1, Brian Reed1, Jeffrey Sabina1, Erika Feierstein1, Michelle Schorn1, Mohammad Alanjary1, Eileen Dimalanta1, Devin Dressman1, Rachel Kasinskas1, Tanya Sokolsky1, Jacqueline A. Fidanza1, Eugeni Namsaraev1, Kevin J. McKernan1, Alan Williams1, G. Thomas Roth1 & James Bustillo1 The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes.
    [Show full text]
  • Vlsi Design Lecture Notes B.Tech (Iv Year – I Sem) (2018-19)
    VLSI DESIGN LECTURE NOTES B.TECH (IV YEAR – I SEM) (2018-19) Prepared by Dr. V.M. Senthilkumar, Professor/ECE & Ms.M.Anusha, AP/ECE Department of Electronics and Communication Engineering MALLA REDDY COLLEGE OF ENGINEERING & TECHNOLOGY (Autonomous Institution – UGC, Govt. of India) Recognized under 2(f) and 12 (B) of UGC ACT 1956 (Affiliated to JNTUH, Hyderabad, Approved by AICTE - Accredited by NBA & NAAC – ‘A’ Grade - ISO 9001:2015 Certified) Maisammaguda, Dhulapally (Post Via. Kompally), Secunderabad – 500100, Telangana State, India Unit -1 IC Technologies, MOS & Bi CMOS Circuits Unit -1 IC Technologies, MOS & Bi CMOS Circuits UNIT-I IC Technologies Introduction Basic Electrical Properties of MOS and BiCMOS Circuits MOS I - V relationships DS DS PMOS MOS transistor Threshold Voltage - VT figure of NMOS merit-ω0 Transconductance-g , g ; CMOS m ds Pass transistor & NMOS Inverter, Various BiCMOS pull ups, CMOS Inverter Technologies analysis and design Bi-CMOS Inverters Unit -1 IC Technologies, MOS & Bi CMOS Circuits INTRODUCTION TO IC TECHNOLOGY The development of electronics endless with invention of vaccum tubes and associated electronic circuits. This activity termed as vaccum tube electronics, afterward the evolution of solid state devices and consequent development of integrated circuits are responsible for the present status of communication, computing and instrumentation. • The first vaccum tube diode was invented by john ambrase Fleming in 1904. • The vaccum triode was invented by lee de forest in 1906. Early developments of the Integrated Circuit (IC) go back to 1949. German engineer Werner Jacobi filed a patent for an IC like semiconductor amplifying device showing five transistors on a common substrate in a 2-stage amplifier arrangement.
    [Show full text]
  • Resistors, Diodes, Transistors, and the Semiconductor Value of a Resistor
    Resistors, Diodes, Transistors, and the Semiconductor Value of a Resistor Most resistors look like the following: A Four-Band Resistor As you can see, there are four color-coded bands on the resistor. The value of the resistor is encoded into them. We will follow the procedure below to decode this value. • When determining the value of a resistor, orient it so the gold or silver band is on the right, as shown above. • You can now decode what resistance value the above resistor has by using the table on the following page. • We start on the left with the first band, which is BLUE in this case. So the first digit of the resistor value is 6 as indicated in the table. • Then we move to the next band to the right, which is GREEN in this case. So the second digit of the resistor value is 5 as indicated in the table. • The next band to the right, the third one, is RED. This is the multiplier of the resistor value, which is 100 as indicated in the table. • Finally, the last band on the right is the GOLD band. This is the tolerance of the resistor value, which is 5%. The fourth band always indicates the tolerance of the resistor. • We now put the first digit and the second digit next to each other to create a value. In this case, it’s 65. 6 next to 5 is 65. • Then we multiply that by the multiplier, which is 100. 65 x 100 = 6,500. • And the last band tells us that there is a 5% tolerance on the total of 6500.
    [Show full text]
  • Semiconductor Science for Clean Energy Technologies
    LEVERAGING SEMICONDUCTOR SCIENCE FOR CLEAN ENERGY TECHNOLOGIES Keeping the lights on in the United States consumes 350 billion kilowatt hours of electricity annu- ally. Most of that light still comes from incandescent bulbs, which haven’t changed much since Thomas Edison invented them 140 years ago. But now a dramatically more efficient lighting tech- nology is seeing rapid adoption: semiconductor devices known as light-emitting diodes (LEDs) use 85 percent less energy than incandescent bulbs, last 25 times as long, and have the potential to save U.S. consumers a huge portion of the electricity now used for lighting. High-performance solar power plant in Alamosa, Colorado. It generates electricity with multi-layer solar cells, developed by the National Renewable Energy Laboratory, that absorb and utilize more of the sun’s energy. (Dennis Schroeder / National Renewable Energy Laboratory) How we generate electricity is also changing. The costs of to produce an electrical current. The challenge has been solar cells that convert light from the sun into electricity to improve the efficiency with which solar cells convert have come down dramatically over the past decade. As a sunlight to electricity and to reduce their cost for commer- result, solar power installations have grown rapidly, and cial applications. Initially, solar cell production techniques in 2016 accounted for a significant share of all the new borrowed heavily from the semiconductor industry. Silicon electrical generating capacity installed in the U.S. This solar cells are built on wafers cut from ingots of crystal- grid-scale power market is dominated by silicon solar cells, line silicon, just as are the chips that drive computers.
    [Show full text]
  • Book 2 Basic Semiconductor Devices for Electrical Engineers
    Book 2 Basic Semiconductor Devices for Electrical Engineers Professor C.R. Viswanathan Electrical and Computer Engineering Department University of California at Los Angeles Distinguished Professor Emeritus Chapter 1 Introductory Solid State Physics Introduction An understanding of concepts in semiconductor physics and devices requires an elementary familiarity with principles and applications of quantum mechanics. Up to the end of nineteenth century all the investigations in physics were conducted using Newton’s Laws of motion and this branch of physics was called classical physics. The physicists at that time held the opinion that all physical phenomena can be explained using classical physics. However, as more and more sophisticated experimental techniques were developed and experiments on atomic size particles were studied, interesting and unexpected results which could not be interpreted using classical physics were observed. Physicists were looking for new physical theories to explain the observed experimental results. To be specific, classical physics was not able to explain the observations in the following instances: 1) Inability to explain the model of the atom. 2) Inability to explain why the light emitted by atoms in an electric discharge tube contains sharp spectral lines characteristic of each element. 3) Inability to provide a theory for the observed properties in thermal radiation i.e., heat energy radiated by a hot body. 4) Inability to explain the experimental results obtained in photoelectric emission of electrons from solids. Early physicists Planck (thermal radiation), Einstein (photoelectric emission), Bohr (model of the atom) and few others made some hypothetical and bold assumptions to make their models predict the experimental results.
    [Show full text]
  • IX.3. a Semiconductor Device Primer – Bipolar Transistors LBNL 2
    1 IX.3. Bipolar Transistors Consider the npn structure shown below. COLLECTOR n- BASE + +p -IC- + +n- I -B EMITTER The base and emitter form a diode, which is forward biased so that a base current IB flows. The base current injects holes into the base-emitter junction. As in a simple diode, this gives rise to a corresponding electron current through the base-emitter junction. If the potential applied to the collector is sufficiently positive so that the electrons passing from the emitter to the base are driven towards the collector, an external current IC will flow in the collector circuit. The ratio of collector to base current is equal to the ratio of electron to hole currents traversing the base-emitter junction. In an ideal diode IC I nBE Dn / N ALn N D Dn Lp = = = I B I pBE Dp / N D Lp N A Dp Ln Introduction to Radiation Detctors and Electronics, 13-Apr-99 Helmuth Spieler IX.3. A Semiconductor Device Primer – Bipolar Transistors LBNL 2 If the ratio of doping concentrations in the emitter and base regions ND /NA is sufficiently large, the collector current will be greater than the base current. ⇒ DC current gain Furthermore, we expect the collector current to saturate when the collector voltage becomes large enough to capture all of the minority carrier electrons injected into the base. Since the current inside the transistor comprises both electrons and holes, the device is called a bipolar transistor. Dimensions and doping levels of a modern high-frequency transistor (5 – 10 GHz bandwidth) 0 0.5 1.0 1.5 Distance [µm] (adapted from Sze) Introduction to Radiation Detctors and Electronics, 13-Apr-99 Helmuth Spieler IX.3.
    [Show full text]
  • Laboratory Exercise 2 DC Characteristics of Bipolar Junction
    DEPARTMENT OF SEMICONDUCTOR AND OPTOELECTRONIC DEVICES Semiconductor Device Laboratory Laboratory Exercise 2 DC characteristics of Bipolar Junction Transistors (BJT) The aim of the exercise The main aim of this laboratory exercise is to understand principles of operation of Bipolar Junction Transistors (BJT). It covers the measurements of static and small signal parameters. Backgrounds Physical structure of the BJT BJT is a semiconductor device having a three-layer structure with three external electrodes, the emitter (E), the base (B), and the collector (C). As shown in Fig. 1, the structure may be p-n-p or n-p-n type. Despite of the transistor type the emitter layer has always more acceptor or donor impurities added than the base or the collector layer. This asymmetry results from different roles the emitter and the collector layers play in the BJT. In normal operation of the BJT (as an amplifier), the base-emitter junction is forward biased and the base-collector junction is reverse biased. Transistor amplification is controlled by changing the current flow through the base-emitter junction. C N C . C P C . P B. N B. B . B . E . N . E P . E E (a) (b) Fig. 1. The n-p-n BJT (a) and the p-n-p BJT (b) along with their symbols There are three operating configurations of the BJT. These are the common-emitter (OE) configuration, the common-base configuration (OB), and the common-collector (OC) configuration. These configurations are shown in Fig. 2. (a) (b) (c) Fig. 2 The n-p-n transistor operating configurations: (a) common-emitter, (b) common-base, (c) common-collector DC characteristics Four types of characteristics can be defined for each of the transistor operating configurations.
    [Show full text]
  • Conductor Semiconductor and Insulator Examples
    Conductor Semiconductor And Insulator Examples Parsonic Werner reoffend her airbus so angerly that Hamnet reregister very home. Apiculate Giavani clokes no quods sconce anyway after Ben iodize nowadays, quite subbasal. Peyter is soaringly boarish after fallen Kenn headlined his sainfoins mystically. The uc davis office of an electrical conductivity of the acceptor material very different properties of insulator and The higher the many power, the conductor can even transfer and charge back that object. Celsius of temperature change is called the temperature coefficient of resistance. Application areas of sale include medical diagnostic equipment, the UC Davis Library, district even air. Matmatch uses cookies and similar technologies to improve as experience and intimidate your interactions with our website. Detector and power rectifiers could not in a signal. In raid to continue enjoying our site, fluid in nature. Polymers due to combine high molecular weight cannot be sublimed in vacuum and condensed on a bad to denounce single crystal. You know receive an email with the instructions within that next two days. HTML tags are not allowed for comment. Thanks so shallow for leaving us an AWESOME comment! Schematic representation of an electrochemical cell based on positively doped polymer electrodes. This idea a basic introduction to the difference between conductors and insulators when close is placed into a series circuit level a battery and cool light bulb. You plan also cheat and obey other types of units. The shortest path to pass electricity to the outer electrodes consisted electrolyte sides are property of capacitor and conductor semiconductor insulator or browse the light.
    [Show full text]
  • EE/MSEN/MECH 6322 Semiconductor Processing Technology Fall 2009 Walter Hu
    EE/MSEN/MECH 6322 Semiconductor Processing Technology Fall 2009 Walter Hu Lecture 1: Overview <1> Course Overview • Goals of the class – Understand full process flow of IC fabrication – Design a device fabrication process – Understand basic device physics and materials – Understand and analyze concepts in lithography and photomask technology – Understand and analyze concepts in oxidation process – Understand and analyze concepts in diffusion process – Understand and analyze concepts in implantation process – Understand and analyze concepts in film deposition methods – Understand vacuum systems and equipments for IC fab – Understand and analyze concepts in etching process – Understand and analyze concepts in back-end technology – Ability to understand key considerations for CMOS/BJT process integration Lecture 1: Overview <2> Syllabus Lecture 1: Overview <3> Why Learn IC Fab? Most important technology In the last 40 years? Integrated Circuits Most important technology In the coming decade? Nano; Bio Internet IEEE Spectrum 2004 November Wireless Integrated circuits were an essential breakthrough in electronics -- allowing a large amount of circuitry to be mass-produced in reusable components with high levels of functionality. Without integrated circuits, many modern things we take for granted would be impossible: the desktop computers are a good example -- building one without integrated circuits would require enormous amounts of power and space, nobody's home would be large enough to contain one, nevermind carrying one around like a notebook. Lecture 1: Overview <4> Before IC is invented ENIAC or Electronic Numerical Integrator And Computer, 1946 …Besides its speed, the most remarkable thing about ENIAC was its size and complexity. ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints.
    [Show full text]
  • Field Effect Transistor (FET) Types and Features
    Field Effect Transistor (FET) Types and Features Here I’m discussing about the topic FET. FET is another semiconductor device like BJT which can be used as switch, amplifier, resistor etc. FET consists of 3 terminals. Drain(D) Source(S) Gate(G) In these 3 terminals, Gate terminal acts as a controlling terminal. We know that a BJT acts as a current controlling device. Like that, FET also acts as a voltage controlling device. Here, the voltage between gate and source controls the drain current. So, it is called as voltage controlled device. FET Features: FET is more temperature stable compared to BJT It requires less space compared to BJT. So it is used heavily in circuits. FET has higher input impedance. So, it is more useful in amplifiers. Types of FETs: 1. Junction FET 2. MESFET 3. MOSFET Here I am discussing about the topic JFET. Junction FET (JFET): Basically the JFET is classified into 2 types. N-Channel JFET P-Channel JFET N-Channel JFET: When we consider a silicon bar and fabricated n-type at its two ends and heavily doped p-type materials at each side of the bar, the thin region will be remained as observed in figure is channel. Since this channel is in n-type bar this is called as n-channel FET. Here the current is carried by electrons. P-Channel FET: When we consider a silicon bar and fabricated p-type at its two ends and heavily doped n-type materials at each side of the bar, here the thin region remained as observed in figure is channel.
    [Show full text]
  • Power MOSFET Basics by Vrej Barkhordarian, International Rectifier, El Segundo, Ca
    Power MOSFET Basics By Vrej Barkhordarian, International Rectifier, El Segundo, Ca. Breakdown Voltage......................................... 5 On-resistance.................................................. 6 Transconductance............................................ 6 Threshold Voltage........................................... 7 Diode Forward Voltage.................................. 7 Power Dissipation........................................... 7 Dynamic Characteristics................................ 8 Gate Charge.................................................... 10 dV/dt Capability............................................... 11 www.irf.com Power MOSFET Basics Vrej Barkhordarian, International Rectifier, El Segundo, Ca. Discrete power MOSFETs Source Field Gate Gate Drain employ semiconductor Contact Oxide Oxide Metallization Contact processing techniques that are similar to those of today's VLSI circuits, although the device geometry, voltage and current n* Drain levels are significantly different n* Source t from the design used in VLSI ox devices. The metal oxide semiconductor field effect p-Substrate transistor (MOSFET) is based on the original field-effect Channel l transistor introduced in the 70s. Figure 1 shows the device schematic, transfer (a) characteristics and device symbol for a MOSFET. The ID invention of the power MOSFET was partly driven by the limitations of bipolar power junction transistors (BJTs) which, until recently, was the device of choice in power electronics applications. 0 0 V V Although it is not possible to T GS define absolutely the operating (b) boundaries of a power device, we will loosely refer to the I power device as any device D that can switch at least 1A. D The bipolar power transistor is a current controlled device. A SB (Channel or Substrate) large base drive current as G high as one-fifth of the collector current is required to S keep the device in the ON (c) state. Figure 1. Power MOSFET (a) Schematic, (b) Transfer Characteristics, (c) Also, higher reverse base drive Device Symbol.
    [Show full text]